Chapter XXVII: Appendix (1)

TABULAR VIEW OF THE CHIEF DIVISIONS OF THE ANIMAL KINGDOM.

(Extinct groups are marked with an asterisk. Groups not represented at all as fossils are marked with two asterisks.)

INVERTEBRATE ANIMALS.

SUB-KINGDOM I.--PROTOZOA.

Animal simple or compound; body composed of "sarcode," not definitely segmented; no nervous system; and no digestive apparatus, beyond occasionally a mouth and gullet.

CLASS I. GREGARINIDÆ.**
CLASS II. RHIZOPODA.
_Order_ 1. _Monera_.**
" 2. _Amoebea_.**
" 3. _Foraminifera_.
" 4. _Radiolaria_ (Polycystines, &c.)
" 5. _Spongida_ (Sponges).
CLASS III. INFUSORIA.**

SUB-KINGDOM II.--COELENTERATA.

Animal simple or compound; body-wall composed of two principal layers; digestive canal freely communicating with the general cavity of the body; no circulating organs, and no nervous system or a rudimentary one; mouth surrounded by tentacles, arranged, like the internal organs, in a "radiate" or star-like manner.

CLASS I. HYDROZOA.
_Sub-class_ 1. _Hydroida_ ("Hydroid Zoophytes"). _Ex._
Fresh-water Polypes,** Pipe-corallines (_Tubularia_), Sea-Firs
(_Sertularia_).
_Sub-class_ 2. _Siphonophora_** ("Oceanic Hydrozoa").
_Ex_. Portuguese Man-of-war (_Physalia_).
_Sub-class_ 3. _Discophora_ ("Jelly-fishes"). Only known as
fossils by impressions of their stranded carcasses.
_Sub-class_ 4. _Lucernarida_ ("Sea-blubbers"). Also only
known as fossils by impressions left in fine-grained strata.
_Sub-class_ 5. _Graptolitidoe_* ("Graptolites").
CLASS II. ACTINOZOA.
_Order_ 1. _Zoantharia_. _Ex_. Sea-anemones**
(_Actinidoe_), Star-corals (_Astroeidoe_).
_Order_ 2. _Alcyonaria_. _Ex_. Sea-pens
(_Pennatula_), Organ-pipe Coral (_Tubipora_),
Red Coral (_Corallium_).
_Order_ 3. _Rugosa_ ("Rugose Corals").
" 4. _Ctenophora_.** _Ex_. Venus's Girdle (_Cestum_).

SUB-KINGDOM III.--ANNULOIDA.

Animals in which the digestive canal is completely shut off from the cavity of the body; a distinct nervous system; a system of branched "water-vessels," which usually communicate with the exterior. Body of the adult often "radiate," and never composed of a succession of definite rings.

CLASS I. ECHINODERMATA.
_Order_ 1. _Crinoidea_ ("Sea-lilies"). _Ex_.
Feather-star (_Comatula_), Stone-lily (_Encrinus_*).
_Order_ 2. _Blastoidea_* ("Pentremites").
" 3. _Cystoidea_* ("Globe-lilies").
" 4. _Ophiuroidea_ ("Brittle-stars"). _Ex_.
Sand-stars (_Ophiura_), Brittle-stars (_Ophiocoma_).
_Order_ 5. _Asteroidea_ ("Star-fishes"). Ex. Cross-fish
(_Uraster_), Sun-star (_Solaster_).
_Order_ 6. _Echinoidea_ ("Sea-urchins"). Ex. Sea-eggs
(_Echinus_), Heart-urchins (_Spatangus_).
_Order_ 7. _Holothuroidea_ ("Sea-cucumbers"). _Ex_.
Trepangs (_Holothuria_).
CLASS II. SCOLECIDA** (Intestinal Worms, Wheel Animalcules, &c.)

SUB-KINGDOM IV.--ANNULOSA.

Animal composed of numerous definite segments placed one behind the other; nervous system forming a knotted cord placed along the lower (ventral) surface of the body.

_Division A. Anarthropoda_. No jointed limbs.

CLASS I. GEPHYREA** ("Spoon-worms").
CLASS II. ANNELIDA. ("Ringed-worms"). _Ex_. Leeches**
(_Hirudinea_), Earthworms** (_Oligochoeta_),
Tube-worms (_Tubicola_), Sea-worms and
Sea-centipedes (_Errantia_).
CLASS III. CHÆTOGNATHA** ("Arrow-worms").

_Division B. Arthropoda or Articulata_. Limbs jointed to the body.

CLASS I. CRUSTACEA ("Crustaceans"). _Ex_. Barnacles and
Acorn-shells (_Cirripedia_), Water-fleas (_Ostracoda_),
Brine-shrimps and Fairy-shrimps (_Phyllopoda_), Trilobites*
(_Trilobita_), King-crabs and Eurypterids* (_Merostomata_),
Wood-lice and Slaters (_Isopoda_), Sand-hoppers
(_Amphipoda_), Lobsters, Shrimps, Hermit-crabs, and
Crabs (_Decapoda_).
CLASS II. ARACHNIDA. _Ex._ Mites (_Acarina_), Scorpions
(_Pedipalpi_), Spiders (_Araneida_).
CLASS III. MYRIAPODA. _Ex._ Centipedes (_Chilopoda_),
Millipedes and Galley-worms (_Chilignatha_).
CLASS IV. INSECTA ("Insects"). _Ex_. Field-bugs (_Hemiptera_);
Crickets, Grasshoppers, &c. (_Orthoptera_); Dragon-flies
and May-flies (_Neuroptera_); Goats and House-flies
(_Diptera_); Butterflies and Moths (_Lepidoptera_);
Bees, Wasps, and Ants (_Hymenoptera_); Beetles
(_Coleoptera_).

SUB-KINGDOM V.--MOLLUSCA.

Animal soft-bodied, generally with a hard covering or shell; no distinct segmentation of the body; nervous system of scattered masses.

CLASS I. POLYZOA ("Sea-Mosses"). _Ex_. Sea-mats (_Flustra_),
Lace-corals (_Fenestellidoe_*).
CLASS II. TUNICATA** ("Tunicaries"). _Ex_. Sea-squirts
(_Ascidia_).
CLASS III. BRACHIOPODA ("Lamp-shells"). _Ex_. Goose-bill
Lamp-shell (_Lingula_).
CLASS IV. LAMELLIBRANCHIATA ("Bivalves"). _Ex_. Oyster
(_Ostrea_), Mussel (_Mytilus_), Scallop (_Pecten_),
Cockle (_Cardium_).
CLASS V. GASTEROPODA ("Univalves"). _Ex_. Whelks
(_Buccinum_), Limpets (_Patella_), Sea-slugs**
(_Doris_), Land-snails (_Helix_).
CLASS VI. PTEROPODA ("Winged Snails"). Ex. _Hyalea, Cleodora_.
CLASS VII. CEPHALOPODA ("Cuttle-fishes"). _Ex_. Calamary
(_Loligo_), Poulpe (_Octopus_), Paper Nautilus
(_Arganauta_), Pearly Nautilus (_Nautilus_), Belemnites,*
Orthoceratites,* Ammonites.*

VERTEBRATE ANIMALS.

SUB-KINGDOM VI.--VERTEBRATA.

Body composed of definite segments arranged longitudinally one behind the other; main masses of the nervous system placed dorsally; a backbone or "vertebral column" in the majority.

CLASS I. PISCES ("Fishes"). _Ex_. Lancelet** (_Amphioxus_);
Lampreys and Hag-fishes (_Marsipobranchii_**); Herring,
Salmon, Perch, &c. (_Teleostei_ or "Bony Fishes");
Gar-pike, Sturgeon, &c. (_Ganoidei_); Sharks, Dog-fishes,
Rays, &c. (_Elasmobranchii_ or "Placoids").
CLASS II. AMPHIBIA ("Amphibians"). Ex. _Labyrinthodontia_,*
Cæcilians,** Newts and Salamanders (_Urodela_), Frogs and
Toads (_Anoura_).
CLASS III. REPTILIA ("Reptiles"). Ex. _Deinosauria_,*
_Pterosauria_,* _Anomodontia_,* Plesiosaurs
(_Sauropterygia_*), Ichthyosaurs (_Ichthyopterygia_*),
Tortoises and Turtles (_Chelonia_), Snakes (_Ophidia_),
Lizards (_Lacertilia_), Crocodiles (_Crocodilia_).
CLASS IV. AVES ("Birds"). _Ex_. Toothed Birds
(_Odontornithes_*); Lizard-tailed Birds (_Archoeopteryx_*);
Ducks, Geese, Gulls, &c. (_Natatores_); Storks, Herons,
Snipes, Plovers, &c. (_Grallatores_); Ostrich, Emeu,
Cassowary, Dinornis,* Æpiornis,* &c. (_Cursores_); Fowls,
Game Birds, and Doves (_Rasores_); Cuckoos, Woodpeckers,
Parrots, &c. (_Scansores_); Crows, Starlings, Finches,
Hummingbirds, Swallows, &c. (_Insessores_); Owls, Hawks,
Eagles, Vultures (_Raptores_).
CLASS V. MAMMALIA ("Quadrupeds"). _Ex_. Duck-mole and Spiny
Ant-eater (_Monotremata_**); Kangaroos, Phalangers,
Opossums, Tasmanian Devil, &c. (_Marsupialia_); Sloths,
Ant-eaters, Armadillos (_Edentata_); Manatees and Dugongs
(_Sirenia_); Whales, Dolphins, Porpoises (_Cetacea_);
Rhinoceros, Tapir, Horses, Hippopotamus, Pigs, Camels and
Llamas, Giraffes, Deer, Antelopes, Sheep, Goats, Oxen
(_Ungulata_); Hyrax (_Hyracoidea_**); Elephants,
Mastodon,* Deinotherium* (_Proboscidea_); Seals,
Walrus, Bears, Dogs, Wolves, Cats, Lions, Tigers, &c.
(_Carnivora_); Hares, Rabbits, Porcupines, Beavers,
Rats, Mice, Lemmings, Squirrels, Marmots, &c. (_Rodentia_);
Bats (_Cheiroptera_); Moles, Shrew-mice, Hedgehogs
(_Insectivora_); Lemurs, Spider-monkeys, Macaques,
Baboons, Apes (_Quadrumana_); Man (_Bimana_).

GLOSSARY.

ABDOMEN (Lat. _abdo_, I conceal). The posterior cavity of the body, containing the intestines and others of the viscera. In many Invertebrates there is no separation of the body-cavity into thorax and abdomen, and it is only in the higher _Annulosa_ that a distinct abdomen can be said to exist.

ABERRANT (Lat. _aberro_, I wander away). Departing from the regular type.

ABNORMAL (Lat. _ab_, from; _norma_, a rule). Irregular; deviating from the ordinary standard.

ACRODUS (Gr. _akros_, high; _odous_, tooth). A genus of the Cestraciont fishes, so called from the elevated teeth.

ACROGENS (Gr. _akros_, high; _gennao_, I produce). Plants which increase in height by additions made to the summit of the stem by the union of the bases of the leaves.

ACROTRETA (Gr. _akros_, high; _tretos_, pierced). A genus of Brachiopods, so called from the presence of a foramen at the summit of the shell.

ACTINOCRINUS (Gr. _aktin_, a ray; _krinon_, a lily). A genus of Crinoids.

ACTINOZOA (Gr. _aktin_, a ray; and _zoön_, an animal). That division of the _Coelenterata_ of which the Sea-anemones may be taken as the type.

ÆGLINA (_Æglé_, a sea-nymph). A genus of Trilobites.

ÆPIORNIS (Gr. _aipus_, huge; _ornis_, bird). A genus of gigantic Cursorial birds.

AGNOSTUS (Gr. _a_, not; _gignosko_, I know). A genus of Trilobites.

ALCES (Lat. _alces_, elk). The European Elk or Moose.

ALECTO (the proper name of one of the Furies). A genus of _Polyzoa_.

ALETHOPTERIS (Gr. _alethes_, true; _pteris_, fern). A genus of Ferns.

ALGÆ. (Lat. _alga_, a marine plant). The order of plants comprising the Sea-weeds and many fresh-water plants.

ALVEOLUS (Lat. _alvus_, belly). Applied to the sockets of the teeth.

AMBLYPTERUS (Gr. _amblus_, blunt; _pteron_, fin). An order of Ganoid Fishes.

AMBONYCHIA (Gr. _ambon_, a boss; _onux_, claw). A genus of Palæozoic Bivalves.

AMBULACRA (Lat. _ambulacrum_, a place for walking). The perforated spaces or "avenues" through which are protruded the tube-feet, by means of which locomotion is effected in the _Echinodermata_.

AMMONITIDÆ. A family of Tetrabranchiate Cephalopods, so called from the resemblance of the shell of the type-genus, _Ammonites_, to the horns of the Egyptian God, Jupiter-Ammon.

AMORPHOZOA (Gr. _a_, without; _morphe_, shape; _zoön_, animal). A name sometimes used to designate the _Sponges_.

AMPHIBIA (Gr. _amphi_, both; _bios_, life). The Frogs, Newts, and the like, which have gills when young, but can always breathe air directly when adult.

AMPHICYON (Gr. _amphi_, both--implying doubt; _kuon_, dog). An extinct genus of _Carnivora_.

AMPHILESTES (Gr. _amphi_, both; _lestes_, a thief). A genus of Jurassic Mammals.

AMPHISPONGIA (Gr. _amphi_, both; _spoggos_, sponge). A genus of Silurian sponges.

AMPHISTEGINA (Gr. _amphi_, both; _stegé_, roof). A genus of _Foraminifera_.

AMPHITHERIUM (Gr. _amphi_, both; _therion_, beast). A genus of Jurassic Mammals.

AMPHITRAGULUS (Gr. _amphi_, both; dim. of _tragos_, goat). An extinct genus related to the living Musk-deer.

AMPLEXUS (Lat. an Ambrace). A genus of Rugose Corals.

AMPYX (Gr. _ampux_, a wreath or wheel). A genus of Trilobites.

ANARTHROPODA (Gr. _a_, without; _arthros_, a joint; _pous_, foot). That division of _Annulose_ animals in which there are no articulated appendages.

ANCHITHERIUM (Gr. _agchi_, near; _therion_, beast). An extinct genus of Mammals.

ANCYLOCERAS (Gr. _agkulos_, crooked; _ceras_, horn). A genus of _Ammonitidoe_.

ANCYLOTHERIUM (Gr. _agkulos_, crooked; _therion_, beast). An extinct genus of Edentate Mammals.

ANDRIAS (Gr. _andrias_, image of man). An extinct genus of tailed Amphibians.

ANGIOSPERMS (Gr. _angeion_, a vessel; _sperma_, seed). Plants which have their seeds enclosed in a seed-vessel.

ANNELIDA (a Gallicised form of _Annulata_). The Ringed Worms, which form one of the divisions of the _Anarthropoda_.

ANNULARIA (Lat. _annulus_, a ring). A genus of Palæozoic plants, with leaves in whorls.

ANNULOSA (Lat. _annulus_). The sub-kingdom comprising the _Anarthropoda_ and the _Arthropoda_ or _Articulata_, in all of which the body is more or less evidently composed of a succession of rings.

ANOMODONTIA (Gr. _anomos_, irregular; _odous_, tooth). An extinct order of Reptiles, often called _Dicynodontia_.

ANOMURA (Gr. _anomos_, irregular; _oura_, tail). A tribe of Decapod _Crustacea_, of which the Hermit-crab is the type.

ANOPLOTHERIDÆ (Gr. _anoplos_, unarmed; _ther_, beast). A family of Tertiary Ungulates.

ANOURA (Gr. _a_, without; _oura_, tail). The order of _Amphibia_ comprising the Frogs and Toads, in which the adult is destitute of a tail. Often, called _Batrachia_.

ANTENNÆ (Lat. _antenna_, a yard-arm). The jointed horns or feelers possessed by the majority of the _Articulata_.

ANTENNULES (dim. of _Antennoe_). Applied to the smaller pair of antennæ in the _Crustacea_.

ANTHRACOSAURUS (Gr. _anthrax_, coal; _saura_, lizard). A genus of Labyrinthodont Amphibians.

ANTHRAPALÆMON (Gr. _anthrax_, coal; _paloemon_, a prawn--originally a proper name). A genus of long-tailed Crustaceans from the Coal-measures.

ANTLERS. Properly the branches of the horns of the Deer tribe (_Cervidoe_), but generally applied to the entire horns.

APIOCRINIDÆ (Gr. _apion_, a pear; _krinon_, lily). A family of Crinoids--the "Pear-encrinites."

APTERYX (Gr. _a_, without; _pterux_, a wing). A wingless bird of New Zealand, belong to the order _Cursores_.

AQUEOUS (Lat. _aqua_, water). Formed in or by water.

ARACHNIDA (Gr. _arachne_, a spider). A class of the _Articulata_, comprising Spiders, Scorpions, and allied animals.

ARBORESCENT. Branched like a tree.

ARCHÆOCIDARIS (Gr. _archaios_, ancient; Lat. _cidaris_, a diadem). A Palæozoic genus of Sea-urchins, related to the existing _Cidaris_.

ARCHÆOCYATHUS (Gr. _archaios_, ancient; _kuathos_, cup). A genus of Palæozoic fossils allied to the Sponges.

ARCHÆOPTERYX (Gr. _archaios_, ancient; _pterux_, a wing). The singular fossil bird which alone constitutes the order of the _Saururoe_.

ARCTOCYON (Gr. _arctos_, bear; _kuon_, dog). An extinct genus of Carnivora.

ARENACEOUS. Sandy, or composed of grains of sand.

ARENICOLITES (Lat. _arena_, sand; _colo_, I inhabit). A genus founded on burrows supposed to be formed by worms resembling the living Lobworms (_Arenicola_).

ARTICULATA (Lat. _articulus_, a joint). A division of the animal kingdom, comprising Insects, Centipedes, Spiders, and Crustaceans, characterised by the possession of jointed bodies or jointed limbs. The term _Arthropoda_ is now more usually employed.

ARTIODACTYLA (Gr. _artios_, even; _daktulos_, a finger or toe). A division of the hoofed quadrupeds (_Ungulata_) in which each foot has an even number of toes (two or four).

ASAPHUS (Gr. _Asaphes_, obscure). A genus of Trilobites.

ASCOCERAS (Gr. _askos_, a leather bottle; _keras_, horn). A genus of Tetrabranchiate Cephalopods.

ASIPHONATE. Not possessing a respiratory tube or siphon. (Applied to a division of the _Lamellibranchiate_ Molluscs.)

ASTEROID (Gr. _aster_, a star; and _eidos_, form). Star-shaped, or possessing radiating lobes or rays like a star-fish.

ASTEROIDEA. An order of _Echinodermata_, comprising the Star-fishes, characterised by their rayed form.

ASTEROPHYLLITES (Gr. _aster_, a star; _phullon_, leaf). A genus of Palæozoic plants, with leaves in whorls.

ASTRÆIDÆ (Gr. _Astroea_, a proper name). The family of the Star-corals.

ASTYLOSPONGIA (Gr. _a_, without; _stulos_, a column; _spoggos_, a sponge). A genus of Silurian Sponges.

ATHYRIS (Gr. _a_, without; _thura_, door). A genus of Brachiopods.

ATRYPA (Gr. _a_, without; _trupa_, a hole). A genus of Brachiopods.

AVES (Lat. _avis_, a bird). The class of the Birds.

AVICULA (Lat. a little bird). The genus of Bivalve Molluscs comprising the Pearl-oysters.

AXOPHYLLUM (Gr. _axon_, a pivot; _phullon_, a leaf). A genus of Rugose Corals.

AZOIC (Gr. _a_, without; _zoé_, life). Destitute of traces of living beings.

BACULITES (Lat. _baculum_, a staff). A genus of the _Ammonitidoe_.

BALÆNA (Lat. a whale). The genus of the Whalebone Whales.

BALANIDÆ (Gr. _balanos_, an acorn). A family of sessile _Cirripedes_, commonly called "Acorn-shells."

BATRACHIA (Gr. _batrachos_, a frog). Often loosely applied to any of the _Amphibia_, but sometimes restricted to the Amphibians as a class, or to the single order of the _Anoura_.

BELEMNITIDÆ (Gr. _belemnon_, a dart). An extinct group of Dibranchiate Cephalopods, comprising the Belemnites and their allies.

BELEMNOTEUTHIS (Gr. _belemnon_, a dart; _teuthis_, a cuttle-fish). A genus allied to the Belemnites proper.

BELINURUS (Gr. _belos_, a dart; _oura_, tail). A genus of fossil King-crabs.

BELLEROPHON (Gr. proper name). A genus of oceanic Univalves (_Heteropoda_).

BELOTEUTHIS (Gr. _belos_, a dart; _teuthis_, a cuttle-fish). An extinct genus of Dibranchiate Cephalopods.

BEYRICHIA (named after Prof. Beyrich). A genus of Ostracode Crustaceans.

BILATERAL. Having two symmetrical sides.

BIMANA (Lat. _Bis_, twice; _manus_, a hand). The order of _Mammalia_ comprising man alone.

BIPEDAL (Lat. _bis_, twice; _pes_, foot). Walking upon two legs.

BIVALVE (Lat. _bis_, twice; _valvoe_, folding-doors). Composed of two plates or valves; applied to the shell of the _Lamellibranchiata_ and _Brachiopoda_, and to the carapace of certain _Crustacea_.

BLASTOIDEA (Gr. _blastos_, a bud; and _eidos_, form). An extinct order of _Echinodermata_, often called _Pentremites_.

BRACHIOPODA (Gr. _brachion_, an arm; _pous_, the foot). A class or the _Molluscoida_, often called "Lamp-shells," characterised by possessing two fleshy arms continued from the sides of the mouth.

BRACHYURA (Gr. _brachus_, short; _oura_, tail). A tribe of the Decapod _Crustaceans_ with short tails (_i.e._, the Crabs).

BRADYPODIDÆ. (Gr. _bradus_, slow; _podes_, feet). The family of _Edentata_ comprising the Sloths.

BRANCHIA (Gr. _bragchia_, the gill of a fish). A respiratory organ adapted to breathe air dissolved in water.

BRANCHIATE. Possessing gills or branchiæ.

BRONTEUS (Gr. _broné_, thunder--an epithet of Jupiter the Thunderer). A genus of Trilobites.

BRONTOTHERIUM (Gr. _bronté_, thunder; _therion_ beast). An extinct genus of Ungulate Quadrupeds.

BRONTOZOUM (Gr. _bronté_, thunder; _zoön_, animal). A genus founded on the largest footprints of the Triassic Sandstones of Connecticut.

BUCCINUM (Lat. _buccinun_, a trumpet). The genus of Univalves comprising the Whelks.

CAINOZOIC (_See_ Kainozoic.)

CALAMITES (Lat. _calamus_, a reed). Extinct plants with reed-like stems, believed to be gigantic representatives of the _Equisetaceoe_.

CALCAREOUS (Lat. _calx_, lime). Composed of carbonate of lime.

CALICE. The little cup in which the polype of a coralligenous Zoophyte (_Actinozoön_) is contained.

CALYMENE (Gr. _kalumené_, concealed). A genus of Trilobites.

CALYX (Lat. a cup). Applied to the cup-shaped body of a _Crinoid_ (_Echinodermata_).

CAMAROPHORIA (Gr. _kamara_, a chamber; _phero_, I carry). A genus of Brachiopods.

CAMELOPARDALIDÆ. (Lat. _camelus_, a camel; _pardalis_, a panther). The family of the Giraffes.

CANINE (Lat. _canis_, a dog). The eye-tooth of Mammals, or the tooth which is placed at or close to the præmaxillary suture in the upper jaw, and the corresponding tooth in the lower jaw.

CARAPACE. A protective shield. Applied to the upper shell of Crabs, Lobsters, and many other _Crustacea_. Also the upper half of the immovable case in which the body of a Chelonian is protected.

CARCHARODON (Gr. _karcharos_. rough; _odous_, tooth). A genus of Sharks.

CARDIOCARPON (Gr. _kardia_, the heart; _karpos_, fruit). A genus of fossil fruit from the Coal-measures.

CARDIUM (Gr. _kardia_, the heart). The genus of Bivalve Molluscs comprising the Cockles. _Cardinia, Cardiola_, and _Cardita_ have the same derivation.

CARNIVORA (Lat. _caro_, flesh; _voro_, I devour). An order of the _Mammalia_. The "Beasts of Prey."

CARNIVOROUS (Lat. _caro_, flesh; _voro_, I devour). Feeding upon flesh.

CARYOCARIS (Gr. _karua_, a nut; _karis_, a shrimp). A genus of Phyllopod Crustaceans.

CARYOCRINUS (Gr. _karua_, a nut; _krinon_, a lily). A genus of Cystideans.

CAUDAL (Lat. _cauda_, the tail). Belonging to the tail.

CAVICORNIA (Lat. _cavus_, hollow; _cornu_, a horn). The "hollow-horned" Ruminants, in which the horn consists of a central bony "horn-core" surrounded by a horny sheath.

CENTRUM (Gr. _kentron_, the point round which a circle is described by a pair of compasses). The central portion or "body" of a vertebra.

CEPHALASPIDÆ. (Gr. _kephale_, head; _aspis_, shield). A family of fossil fishes.

CEPHALIC (Gr. _kephale_, head). Belonging to the head.

CEPHALOPODA (Gr. _kephale_; and _podes_, feet). A class of the _Mollusca_, comprising the Cuttle-fishes and their allies, in which there is a series of arms ranged round the head.

CERATIOCARIS (Gr. _keras_, a horn; _karis_, a shrimp). A genus of Phyllopod Crustaceans.

CERATITES (Gr. _keras_, a horn). A genus of _Ammonitidoe_.

CERATODUS (Gr. _keras_, a horn; _odous_, tooth). A genus of Dipnoous fishes.

CERVICAL (Lat. _cervix_, the neck). Connected with or belonging to the region of the neck.

CERVIDÆ (Lat. _cervus_, a stag). The family of the Deer.

CESTRAPHORI (Gr. _kestra_, a weapon; _phero_, I carry). The group of the "Cestraciont Fishes," represented at the present day by the Port-Jackson Shark; so called from their defensive spines.

CETACEA (Gr. _ketos_, a whale). The order of Mammals comprising the Whales and the Dolphins.

CETIOSAURUS (Gr. _ketos_, whale; _saura_, lizard). A genus of Deinosaurian Reptiles.

CHEIROPTERA (Gr. _cheir_, hand; _pteron_, wing). The Mammalian order of the Bats.

CHEIROTHERIUM (Gr. _cheir_, hand; _therion_, beast). The generic name applied originally to the hand-shaped footprints of Labyrinthodonts.

CHEIRURUS (Gr. _cheir_, hand; _oura_, tail). A genus of Trilobites.

CHELONIA (Gr. _cheloné_, a tortoise). The Reptilian order of the Tortoises and Turtles.

CHONETES (Gr. _choné_ or _choané_, a chamber or box). A genus of Brachiopods.

CIDARIS (Lat. a diadem). A genus of Sea-urchins.

CLADODUS (Gr. _klados_, branch; _odous_, tooth). A genus of Fishes.

CLATHROPORA (Lat. _clathti_, a trellis; _porus_, a pore). A genus of Lace-corals (_Polyzoa_).

CLISIOPHYLLUM (Gr. _klision_, a hut; _phullon_, leaf). A genus of Rugose Corals.

CLYMENIA (_Clumene_, a proper name). A genus of Tetrabranchiate Cephalopods.

COCCOSTEUS (Gr. _kokkos_, berry; _osteon_, bone). A genus of Ganoid Fishes.

COCHLIODUS (Gr. _kochlion_, a snail-shell; _odous_, tooth). A genus of Cestraciont Fishes.

COELENTERATA (Gr. _koilos_, hollow; _enteron_, the bowel). The sub-kingdom which comprises the _Hydrozoa_ and _Actinozoa_. Proposed by Frey and Leuckhart in place of the old term _Radiata_, which included other animals as well.

COLEOPTERA (Gr. _koleos_, a sheath; _pteron_, wing). The order of Insects (Beetles) in which the anterior pair of wings are hardened, and serve as protective cases for the posterior pair of membranous wings.

COLOSSOCHELYS (Gr. _kolossos_, a gigantic statue; _chelus_, a tortoise). A huge extinct Land-tortoise.

COMATULA (Gr. _koma_, the hair). The Feather-star, so called in allusion to its tress-like arms.

CONDYLE (Gr. _kondulos_, a knuckle). The surface by which one bone articulates with another. Applied especially to the articular surface or surfaces by which the skull articulates with the vertebral column.

CONIFERÆ (Lat. _conus_, a cone; _fero_, I carry). The order of the Firs, Pines, and their allies, in which the fruit is generally a "cone" or "fir-apple."

CONULARIA (Lat. _conulus_, a little-cone). An extinct genus of Pteropods.

COPRALITES (Gr. _kopros_, dung; _lithos_, stone). Properly applied to the fossilised excrements of animals; but often employed to designate phosphatic concretions which are not of this nature.

CORALLITE. The corallum secreted by an _Actinozoön_ which consists of a single polype; or the portion of a composite corallum which belongs to, and is secreted by, an individual polype.

CORALLUM (from the Latin for Red Coral). The hard structures deposited in, or by the tissues of an _Actinozoön_,--commonly called a "coral."

CORIACEOUS (Lat. _corium_. hide). Leathery.

CORYPHODON (Gr. _korus_, helmet; _odous_, tooth). An extinct genus of Mammals, allied to the Tapirs.

CRANIUM (Gr. _kranion_, the skull). The bony or cartilaginous case in which the brain is contained.

CRETACEOUS (Lat. _creta_, chalk). The formation which in Europe contains white chalk as one of its most conspicuous members.

CRINOIDEA (Gr. _krinon_, a lily; _eidos_, form). An order of _Echinodermata_, comprising forms which are usually stalked, and sometimes resemble lilies in shape.

CRIOCERAS (Gr. _krios_, a ram; _keras_, a horn). A genus of _Ammonitidoe_.

CROCODILIA (Gr. _krokodeilos_, a crocodile). An order of Reptiles.

CROSSOPTERYGIDÆ. (Gr. _krossotos_, a fringe; _pterux_, a fin). A sub-order of Ganoids in which the paired fins possess a central lobe.

CRUSTACEA (Lat. _crusta_, a crust). A class of Articulate animals, comprising Crabs, Lobsters, &c., characterised by the possession of a hard shell or crust, which they cast periodically.

CRYPTOGAMS (Gr. _kruptos_, concealed; _gamos_, marriage). A division of plants in which the organs of reproduction are obscure and there are no true flowers.

CTENACANTHUS (Gr. _kteis_, a comb; _akantha_, a thorn). A genus of fossil fishes, named from its fin-spines.

CTENOID (Gr. _kteis_, a comb; _eidos_, form). Applied to those scales of fishes the hinder margins of which are fringed with spines or comb-like projections.

CURSORES (Lat. _curro_, I run). An order of _Aves_, comprising birds destitute of the power of flight, but formed for running vigorously (_e.g._, the Ostrich and Emeu).

CUSPIDATE. Furnished with small pointed eminences or "cusps."

CYATHOCRINUS (Gr. _kuathos_, a cup; _krinon_, a lily). A genus of Crinoids.

CYATHOPHYLLUM (Gr. _kuathos_, a cup; _phullon_, a leaf). A genus of Rugose Corals.

CYCLOID (Gr. _kuklos_, a circle; _eidos_, form). Applied to those scales of fishes which have a regularly circular or elliptical outline with an even margin.

CYCLOPHTHALMUS (Gr. _kuklos_, a circle; _ophthalmos_, eye). A genus of fossil Scorpions.

CYCLOSTOMI (Gr. _kuklos_, and _stoma_, mouth). Sometimes used to designate the Hag-fishes and Lampreys, forming the order _Marsipobranchii_.

CYPRÆA (a name of Venus). The genus of Univalve Molluscs comprising the Cowries.

CYRTOCERAS (Gr. _kurtos_. crooked; _keras_, horn). A genus of Tetrabranchiate Cephalopods.

CYSTIPHYLLUM (Gr. _kustis_, a bladder; _phullon_, a leaf). A genus of Rugose Corals.

CYSTOIDEA (Gr. _kustis_, a bladder; _eidos_, form). The "Globe-crinoids," an extinct order of _Echinodermata_.

DADOXYLON (Gr. _dadion_, a torch; _xulon_, wood). An extinct genus of Coniferous trees.

DECAPODA (Gr. _deka_, ten; _podes_, feet). The division of _Crustacea_ which have ten feet; also the family of Cuttle-fishes, in which there are ten arms or cephalic processes.

DECIDUOUS (Lat. _decido_, I fall off). Applied to parts which fall off or are shed during the life of the animal.

DEINOSAURIA (Gr. _deinos_, terrible; _saura_, lizard). An extinct order of Reptiles.

DEINOTHERIUM (Gr. _deinos_, terrible; _therion_, beast). An extinct genus of Proboscidean Mammals.

DENDROGRAPTUS (Gr. _dendron_, tree; _grapho_, I write). A genus of Graptolites.

DESMIDIÆ. Minute fresh-water plants, of a green colour, without a siliceous epidermis.

DIATOMACEÆ (Gr. _diatemno_, I sever). An order of minute plants which are provided with siliceous envelopes.

DIBRANCHIATA (Gr. _dis_; twice; _bragchia_, gill). The order of _Cephalopoda_ (comprising the Cuttle-fishes, &c.) in which only two gills are present.

DICERAS (Gr. _dis_, twice; _keras_, horn). An extinct genus of Bivalve Molluscs.

DICTYONEMA (Gr. _diktuon_, a net; _nema_, thread). An extinct genus of _Polyzoa_.

DICYNODONTIA (Gr. _dis_, twice; _kuon_, dog; _odous_, tooth). An extinct order of Reptiles.

DIDYMOGRAPTUS (Gr. _didumos_, twin; _grapho_, I write). A genus of Graptolites.

DIMORPHODON (Gr. _dis_, twice; _morphé_, shape; _oduos_, tooth). A genus of Pterosaurian reptiles.

DINICHTHYS (Gr. _deinos_, terrible; _ichthus_, fish). An extinct genus of Fishes.

DINOCERAS (Gr. _deinos_, terrible; _keras_, horn). An extinct genus of Mammals.

DINOPHIS (Gr. _deinos_, terrible; _ophis_, snake). An extinct genus of Snakes.

DINORNIS (Gr. _deinos_, terrible; _ornis_, bird). An extinct genus of Birds.

DIPLOGRAPTUS (Gr. _diplos_, double; _grapho_, I write). A genus of Graptolites.

DIPNOI (Gr. _dis_, twice; _pnoé_, breath). An order of Fishes, comprising the Mud-fishes, so called in allusion to their double mode of respiration.

DIPROTODON (Gr. _dis_, twice; _protos_, first; _odous_, tooth). A genus of extinct Marsupials.

DIPTERA (Gr. _dis_, twice; _pteron_, wing). An order of Insects characterised by the possession of two wings.

DISCOID (Gr. _diskos_, a quoit; _eidos_, form). Shaped like a round plate or quoit.

DOLOMITE (named after M. Dolomieu). Magnesian limestone.

DORSAL (Lat. _dorsum_, the back). Connected with or placed upon the back.

DROMATHERIUM (Gr. _dromaios_, nimble; _therion_, beast). A genus of Triassic Mammals.

DRYOPITHECUS (Gr. _drus_, an oak; _pithekos_, an ape). An extinct genus of Monkeys.

ECHINODERMATA (Gr. _echinos_; and _derma_, skin). A class of animals comprising the Sea-urchins, Star-fishes, and others, most of which have spiny skins.

ECHINOIDEA (Gr. _echinos_; and _eidos_, form). An order of _Echinodermata_, comprising the Sea-urchins.

EDENTATA (Lat. _e_, without; _dens_, tooth). An order of _Mammalia_ often called _Bruta_.

EDENTULOUS. Toothless, without any dental apparatus. Applied to the mouth of any animal, or to the hinge of the Bivalve Molluscs.

ELASMOBRANCHII (Gr. _elasma_, a plate; _bragchia_, gill). An order of Fishes, including the Sharks and Rays.

ENALIOSAURIA (Gr. _enalios_, marine; _saura_, lizard), Sometimes employed as a common term to designate the extinct Reptilian orders of the _Ichthyosauria_ and _Plesiosauria_.

EOCENE (Gr. _eos_, dawn; _kainos_, new or recent). The lowest division of the Tertiary rocks, in which species of existing shells are to a small extent represented.

EOPHYTON (Gr. _eos_, dawn; _phuton_, a plant). A genus of Cambrian fossils, supposed to be of a vegetable nature.

EOZOÖN (Gr. _eos_, dawn; _zoön_, animal). A genus of chambered calcareous organisms found in the Laurentian and Huronian formations.

EQUILATERAL (Lat. _oequus_, equal; _latus_, side). Having its sides equal. Usually applied to the shells of the _Brachiopoda_. When applied to the spiral shells of the _Foraminifera_, it means that all the convolutions of the shell lie in the same plane.

EQUISETACEÆ (Lat. _equus_, horse; _seta_, bristle). A group of Cryptogamous plants, commonly known as "Horse-tails."

EQUIVALVE (Lat. _oequus_, equal; _valvoe_, folding-doors). Applied to shells which are composed of two equal pieces or valves.

ERRANTIA (Lat. _erro_, I wander). An order of _Annelida_, often called _Nereidea_, distinguished by their great locomotive powers.

EUOMPHALUS (Gr. _eu_, well; _omphalos_, navel). An extinct genus of Univalve Molluscs.

EURYPTERIDA (Gr. _eurus_, broad; _pteron_, wing). An extinct sub-order of _Crustacea_.

EXOGYRA (Gr. _exo_, outside; _guros_, circle). An extinct genus of Oysters.

FAUNA (Lat. _Fauni_, the rural deities of the Romans). The general assemblage of the animals of any region or district.

FAVOSITES (Lat. _favus_, a honeycomb). A genus of Tabulate Corals.

FENESTELLIDÆ. (Lat. _fenestella_, a little window). The "Lace-corals," a group of Palæozoic Polyzoans.

FILICES (Lat. _filix_, a fern). The order of Cryptogamic plants comprising the Ferns.

FILIFORM (Lat. _filum_, a thread; _forma_, shape). Thread-shaped.

FLORA (Lat. _Flora_, the goddess of flowers). The general assemblage of the plants of any region or district.

FORAMINIFERA (Lat. _foramen_, an aperture; _fero_, I carry). An order of Protozoa, usually characterised by the possession of a shell perforated by numerous pseudopodial apertures.

FRUGIVOROUS (Lat. _frux_, fruit; _voro_, I devour). Living upon fruits.

FUCOIDS (Lat. _fucus_, sea-weed; Gr. _eidos_, likeness). Fossils, often of an obscure nature, believed to be the remains of sea-weeds.

FUSULINA (Lat. _fusus_, a spindle). An extinct genus of _Foraminifera_.

GANOID (Gr, _ganos_, splendour, brightness). Applied to those scales or plates which are composed of an inferior layer of true bone covered by a superior layer of polished enamel.

GANOIDEI. An order of Fishes.

GASTEROPODA (Gr. _gaster_, stomach; _pous_, foot). The class of the Mollusca comprising the ordinary Univalves, in which locomotion is usually effected by a muscular expansion of the under surface of the body (the "foot").

GLOBIGERINA (Lat. _globus_, a globe; _gero_, I carry). A genus of _Foraminifera_.

GLYPTODON (Gr. _glupho_, I engrave; _odous_, tooth). An extinct genus of Armadillos, so named in allusion to the fluted teeth.

GONIATITES (Gr. _gonia_, angle). A genus of Tetrabranchiate Cephalopods.

GRALLATORES (Lat. _gralloe_, stilts). The order of the long-legged Wading Birds.

GRAPTOLITIDÆ. (Gr. _grapho_, I write; _lithos_, stone). An extinct sub-class of the _Hydrozoa_.

GYMNOSPERMS (Gr. _gumnos_, naked; _sperma_, seed). The Conifers and Cycads, in which the seed is not protected within a seed-vessel.

HALITHERIUM (Gr. _hals_, sea; _therion_, beast). An extinct genus of Sea-cows (_Sirenia_).

HAMITES (Lat. _hamus_, a hook). A genus of the _Ammonitidoe_.

HELIOPHYLLUM (Gr. _helios_, the sun; _phullon_, leaf). A genus of Rugose Corals.

HELLADOTHERIUM (Gr. _Hellas_, Greece; _therion_, beast). An extinct genus of Ungulate Mammals.

HEMIPTERA (Gr. _hemi_, and _pteron_, wing). An order of Insects in which the anterior wings are sometimes "hemelytra."

HESPERORNIS (Gr. _Hesperos_, the evening star; _ornis_, bird). An extinct genus of Birds.

HETEROCERCAL (Gr. _heteros_, diverse; _kerkos_, tail). Applied to the tail of Fishes when it is unsymmetrical, or composed of two unequal lobes.

HETEROPODA (Gr. _heteros_, diverse; _podes_, feet). An aberrant group of the Gasteropods, in which the foot is modified so as to form a swimming organ.

HIPPARION (Gr. _hipparion_, a little horse). An extinct genus of _Equidoe_.

HIPPOPOTAMUS (Gr. _hippos_, horse; _potamos_, river). A genus of Hoofed Quadrupeds--the "River-horses."

HIPPURITIDÆ. (Gr. _hippos_, horse; _oura_, tail). An extinct family of Bivalve Molluscs.

HOLOPTYCHIUS (Gr. _holos_, whole; _ptucé_, wrinkle). An extinct genus of Ganoid Fishes.

HOLOSTOMATA (Gr. _holos_, whole; _stoma_, mouth). A division of _Gasteropodous Molluscs_, in which the aperture of the shell is rounded, or "entire."

HOLOTHUROIDEA (Gr. _holothourion_, and _eidos_, form). An order of _Echinodermata_ comprising the Trepangs.

HOMOCERCAL (Gr. _homos_, same; _kerkol_, tail). Applied to the tail of Fishes when it is symmetrical, or composed of two equal lobes.

HYBODUNTS (Gr. _hubos_, curved; _odous_, tooth). A group of Fishes of which _Hybodus_ is the type-genus.

HYDROIDA (Gr. _hudra_; and _eidos_, form). The sub-class of the _Hydrozoa_, which comprises the animals most nearly allied to the Hydra.

HYDROZOA (Gr. _hudra_; and _zoön_, animal). The class of the _Coelenterata_ which comprises animals constructed after the type of the Hydra.

HYMENOPTERA (Gr. _humen_, a membrane; _pteron_, a wing). An order of Insects (comprising Bees, Ants, &c.) characterised by the possession of four membranous wings.

ICHTHYODORULITE (Gr. _ichthus_, fish; _dorus_, spear; _lithos_, stone). The fossil fin-spine of Fishes.

ICHTHYOPTERYGIA (Gr. _ichthus_; _pterux_, wing). An extinct order of Reptiles.

ICHTHYORNIS (Gr. _ichthus_, fish; _ornis_, bird). An extinct genus of Birds.

ICHTHYOSAURIA (Gr. _ichthus_; _saura_, lizard). Synonymous with _Ichthyopterygia_.

IGUANODON (_Iguana_, a living lizard; Gr. _odous_, tooth). A genus of Deinosaurian Reptiles.

INCISOR (Lat. _incido_, I cut). The cutting teeth fixed in the intermaxillary bones of the _Mammalia_, and the corresponding teeth in the lower jaw.

INEQUILATERAL. Having the two sides unequal, as in the case of the shells of the ordinary bivalves (_Lamellibranchiata_). When applied to the shells of the _Foraminifera_, it implies that the convolutions of the shell do not lie in the same plane, but are obliquely wound round an axis.

INEQUIVALVE. Composed of two unequal pieces or valves.

INOCERAMUS (Gr. _is_, a fibre; _keramos_, an earthen vessel). An extinct genus of Bivalve Molluscs.

INSECTA (Lat. _inseco_, I cut into). The class of articulate animals commonly known as Insects.

INSECTIVORA (Lat. _insectum_, an insect; _voro_, I devour). An order of Mammals.

INSECTIVOROUS. Living upon Insects.

INSESSORES (Lat. _insedeo_, I sit upon). The order of the Perching Birds, often called _Passeres_.

INTERAMBULACRA. The rows of plates in an _Echinoid_ which are not perforated for the emission of the "tube-feet."

INTERMMAXILLÆ or PRÆMAXILLÆ. The two bones which are situated between the two superior maxillæ in _Vertebrata_. In man, and some monkeys, the præmaxillæ anchylose with the maxillæ, so as to be irrecognisable in the adult.

INVERTEBRATA (Lat. _in_, without; _vertebra_, a bone of the back). Animals without a spinal column or backbone.

ISOPODA. (Gr. _isos_, equal; _podes_, feet). An order of _Crustacea_ in which the feet are like one another and equal.

KAINOZOIC (Gr. _kainos_, recent; _zoe_, life). The Tertiary period in Geology comprising those formations in which the organic remains approximate more or less closely to the existing fauna and flora.

LABYRINTHODONTIA (Gr. _laburinthos_, a labyrinth; _odous_, tooth). An extinct order of _Amphibia_, so called from the complex microscopic structure of the teeth.

LACERTILIA (Lat. _lacerta_, a lizard). An order of _Reptilia_ comprising the Lizards and Slow-worms.

LAMELLIBRANCHIATA (Lat. _lamella_, a plate; Gr. _bragchia_, gill). The class of _Mollusca_ comprising the ordinary bivalves, characterised by the possession of lamellar gills.

LEPIDODENDRON (Gr. _lepis_, a scale; _dendron_, a tree). A genus of extinct plants, so named from the scale-like scars upon the stem left by the falling off of the leaves.

LEPIDOPTERA (Gr. _lepis_, a scale; _pteron_, a wing). An order of Insects, comprising Butterflies and Moths, characterised by possessing four wings which are usually covered with minute scales.

LEPIDOSIREN (Gr. _lepis_, a scale; _seiren_, a siren--the generic name of the Mud-eel or _Siren lacertina_). A genus of Dipnoous fishes, comprising the "Mud-fishes."

LEPIDOSTROBUS (Gr. _lepis_, a scale; _strobilos_, a fir-cone). A genus founded on the cones of _Lepidodendron_.

LEPTÆNA (Gr. _leptos_. slender). A genus of Brachiopods.

LINGULA (Lat. _lingula_, a little tongue). A genus of Brachiopods.

LYCOPODIACEÆ (Gr. _lupos_, a wolf; _pous_, foot). The group of Cryptogamic plants generally known as "Club-mosses."

MACHÆRACANTHUS (Gr. _machaira_, a sabre; _acantha_, thorn or spine). An extinct genus of Fishes.

MACHAIRODUS (Gr. _machaira_, a sabre; _odous_, tooth). An extinct genus of Carnivora.

MACROTHERIUM (Gr. _makros_, long; _therion_. beast). An extinct genus of Edentata.

MACRURA (Gr. _makros_, long; _oura_, tail). A tribe of Decapod _Crustaceans_ with long tails (e.g., the Lobster, Shrimp, &c.)

MAMMALIA (Lat. _mamma_, the breast). The class of Vertebrate animals which suckle their young.

MANDIBLE (Lat. _mandibulum_, a jaw). The upper pair of jaws in Insects; also applied to one of the pairs of jaws in _Crustacea_ and Spiders, to the beak of Cephalopods, the lower jaw of Vertebrates, &c.

MANTLE. The external integument of most of the Mollusca, which is largely developed, and forms a cloak in which the viscera are protected. Technically called the "pallium."

MANUS (Lat. the hand). The hand of the higher Vertebrates.

MARSIPOBRANCHII (Gr. _marsipos_, a pouch; _bragchia_, gill). The order of Fishes comprising the Hag-fishes and Lampreys, with pouch-like gills.

MARSUPIALIA (Lat. _marsupium_, a pouch). An order of Mammals in which the females mostly have an abdominal pouch in which the young are carried.

MASTODON (Gr. _mastos_, nipple; _odous_, tooth). An extinct genus of Elephantine Mammals.

MEGALONYX (Gr. _megas_, great; _onux_, nail). An extinct genus of Edentate Mammals.

MEGALOSAURUS (Gr. _megas_, great; _saura_, lizard). A genus of Deinosaurian Reptiles.

MEGATHERIUM (Gr. _megas_, great; _therion_, beast). An extinct genus of Edentata.

MESOZOIC (Gr. _mesos_, middle; and _zoe_, life). The Secondary period in Geology.

MICROLESTES (Gr. _mikros_, little; _lestes_, thief). An extinct genus of Triassic Mammals.

MILLEPORA (Lat. _mille_, one thousand; _porus_, a pore). A genus of "Tabulate Corals."

MIOCENE (Gr. _meion_, less; _kainol_, new). The Middle Tertiary period.

MOLARS (Lat. _mola_, a mill). The "grinders" in man, or the teeth in diphyodont Mammals which are not preceded by milk-teeth.

MOLLUSCA (Lat. _mollis_, soft). The sub-kingdom which includes the Shell-fish proper, the _Polyzoa_, the _Tunicata_, and the Lamp-shells; so called from the generally soft nature of their bodies.

MOLLUSCOIDA (_Mollusca_; Gr. _eidos_, form). The lower division of the _Mollusca_, comprising the _Polyzoa, Tunicata_, and _Brachiopoda_.

MONOGRAPTUS (Gr. _monos_, single; _grapho_, I write). A genus of Graptolites.

MYLODON (Gr. _mulos_, a mill; _odous_, tooth). An extinct genus of Edentate Mammals.

MYRIAPODA or MYRIOPODA (Gr. _murios_, ten thousand; _podes_, feet). A class of _Arthropoda_ comprising the Centipedes and their allies, characterised by their numerous feet.

NATATORES (Lat. _nare_, to swim). The order of the Swimming Birds.

NATATORY (Lat. _nare_, to swim). Formed for swimming.

NAUTILOID. Resembling the shell of the _Nautilus_ in shape.

NERVURES (Lat. _nervus_, a sinew). The ribs which support the membranous wings of insects.

NEUROPTERA (Gr. _neuron_, a nerve; _pteron_, a wing). An order of Insects characterised by four membranous wings with numerous reticulated nervures (_e.g._, Dragon-flies).

NEUROPTERIS (Gr. _neuron_, a nerve; _pteris_, a fern). An extinct genus of Ferns.

NOTHOSAURUS (Gr. _nothos_, spurious; _saura_, lizard). A genus of _Plesiosaurian_ Reptiles.

NOTOCHORD (Gr. _notos_, back; _chorde_, string). A cellular rod which is developed in the embryo of Vertebrates immediately beneath the spinal cord, and which is usually replaced in the adult by the vertebral column. Often it is spoken of as the "chorda dorsalis."

NUDIBRANCHIATA (Lat. _nudus_, naked; and Gr. _bragchia_, gill). An order of the _Gasteropoda_ in which the gills are naked.

NUMMULINA (Lat. _nummus_, a coin). A genus of _Foraminifera_, comprising the coin-shaped "Nummulites."

OBOLELLA (Lat. dim. of _obolus_, a small coin). An extinct genus of Brachiopods.

OCCIPITAL. Connected with the _occiput_, or the back part of the head.

OCEANIC. Applied to animals which inhabit the open ocean (= pelagic).

ODONTOPTERYX (Gr. _oduos_, tooth; _pterux_, wing). An extinct genus of Birds.

ODONTORNITHES (Gr. _oduos_, tooth; _ornis_, bird). The extinct order of Birds, comprising forms with distinct teeth in sockets.

OLIGOCENE (Gr. _oligos_, few; _kainos_, new). A name used by many Continental geologists as synonymous with the Lower Miocene.

OPHIDIA (Gr. _ophis_, a serpent). The order of Reptiles comprising the Snakes.

OPHIUROIDEA (Gr. _ophis_, snake; _oura_, tail; _eidos_, form). An order of _Echinodermata_, comprising the Brittle-stars and Sand-stars.

ORNITHOSCELIDA (Gr. _ornis_, bird; _skelos_, leg). Applied by Huxley to the Deinosaurian Reptiles, together with the genus _Compsognathus_, on account of the bird-like character of their hind-limbs.

ORTHIS (Gr. _orthos_, straight). A genus of Brachiopods, named in allusion to the straight hinge-line.

ORTHOCERATIDÆ (Gr. _orthos_, straight; _keras_, horn). A family of the _Nautilidoe_, in which the shell is straight, or nearly so.

ORTHOPTERA (Gr. _orthos_, straight; _pteron_, wing). An order of Insects.

OSTEOLEPIS (Gr. _osteon_, bone; _lepis_, scale). An extinct genus of Ganoid Fishes.

OSTRACODA (Gr. _ostrakon_, a shell). An order of small Crustaceans which are enclosed in bivalve shells.

OTODUS (Gr. _ota_, ears; _odous_, tooth). An extinct genus of Sharks.

OUDENODON (Gr. _ouden_, none; _odous_, tooth). A genus of Dicynodont Reptiles.

OVIBUS (Lat. _ovis_, sheep; _bos_, ox). The genus comprising the Musk-ox.

PACHYDERMATA (Gr. _pachus_, thick; _derma_, skin). An old Mammalian order constituted by Cuvier for the reception of the Rhinoceros, Hippopotamus, Elephant, &c.

PALÆASTER (Gr. _palaios_, ancient; _aster_, star). An extinct genus of Star-fishes.

PALÆOCARIS (Gr. _palaios_, ancient; _karis_, shrimp). An extinct genus of Decapod Crustaceans.

PALÆOLITHIC (Gr. _palaios_, ancient; _lithos_, stone). Applied to the rude stone implements of the earliest known races of men, to the men who made these implements, or to the period at which they were made.

PALÆONTOLOGY (Gr. _palaios_, ancient; and _logos_, discourse). The science of fossil remains or of extinct organised beings.

PALÆOPHIS (Gr. _palaios_, ancient; _ophis_, serpent). An extinct genus of Snakes.

PALÆOSAURUS (Gr. _palaios_, ancient; _saura_, lizard). A genus of Thecodont Reptiles.

PALÆOTHERIDÆ. (Gr. _palaios_, ancient; _ther_, beast). A group of Tertiary Ungulates.

PALÆOZOIC (Gr. _palaios_, ancient; and _zoe_, life). Applied to the oldest of the great geological epochs.

PARADOXIDES (Lat. _paradoxus_, marvellous). A genus of Trilobites.

PATAGIUM (Lat. the border of a dress). Applied to the expansion of the integument by which Bats, Flying Squirrels, and other animals support themselves in the air.

PECOPTERIS (Gr. _peko_, I comb; _pteris_, a fern). An extinct genus of Ferns.

PECTEN (Lat. a comb). The genus of Bivalve Molluscs comprising the Scallops.

PECTORAL (Lat. _pectus_, chest). Connected with, or placed upon, the chest.

PENTACRINUS (Gr. _penta_, five; _krinon_, lily). A genus of Crinoids in which the column is five-sided.

PENTAMERUS (Gr. _penta_, five; _meros_, part). An extinct genus of Brachiopods.

PENTREMITES (Gr. _penta_, five; _trema_, aperture). A genus of _Blastoidea_, so named in allusion to the apertures at the summit of the calyx.

PERENNIBRANCHIATA (Lat. _perennis_, perpetual; Gr. _bragchia_, gill). Applied to those Amphibia in which the gills are permanently retained throughout life.

PERISSODACTYLA (Gr. _perissos_, uneven; _daktulos_, finger). Applied to those Hoofed Quadrupeds (_Ungulata_) in which the feet have an uneven number of toes.

PETALOID. Shaped like the petal of a flower.

PHACOPS (Gr. _phaké_, a lentil; _ops_, the eye). A genus of Trilobites.

PHALANGES (Gr. _phalanx_, a row). The small bones composing the digits of the higher _Vertebrata_. Normally each digit has three phalanges.

PHANEROGAMS (Gr. _phaneros_, visible; _gamos_, marriage). Plants which have the organs of reproduction conspicuous, and which bear true flowers.

PHARYNGOBRANCHII (Gr. _pharugx_, pharynx; _bragchia_, gill). The order of Fishes comprising only the Lancelet.

PHASCOLOTHERIUM (Gr. _phaskolos_, a pouch; _therion_, a beast). A genus of Oolitic Mammals.

PHRAGMACONE (Gr. _phragma_, a partition; and _konos_, a cone). The chambered portion of the internal shell of a _Belemnite_.

PHYLLOPODA (Gr. _phullon_, leaf; and _pous_, foot). An order of _Crustacea_.

PINNATE (Lat. _pinna_, a feather). Feather-shaped; or possessing lateral processes.

PINNIGRADA (Lat. _pinna_, a feather; _gradior_, I walk). The group of _Carnivora_, comprising the Seals and Walruses, adapted for an aquatic life. Often called _Pinnipedia_.

PINNULÆ. (Lat. dim. of _pinna_). The lateral processes of the arms of _Crinoids_.

PISCES (Lat. _piscis_, a fish). The class of Vertebrates comprising the Fishes.

PLACOID (Gr. _plax_, a plate; _eidos_, form). Applied to the irregular bony plates, grains, or spines which are found in the skin of various fishes (_Elasmobranchii_).

PLAGIOSTOMI (Gr. _plagios_, transverse; _stoma_, mouth). The Sharks and Rays, in which the mouth is transverse, and is placed on the under surface of the head.

PLATYCERAS (Gr. _platus_, broad; _keras_, horn). A genus of Univalve Molluscs.

PLATYCRINUS (Gr. _platus_, broad; _krinom_, lily). A genus of Crinoidea.

PLATYRHINA (Gr. _platus_, broad; _rhines_, nostrils). A group of the _Quadrumana_.

PLATYSOMUS (Gr. _platus_, wide; _soma_, body). A genus of Ganoid Fishes.

PLEISTOCENE (Gr. _pleistos_, most; _kainos_, new). Often used as synonymous with "Post-Pliocene."

PLEUROTOMARIA (Gr. _pleura_, the side; _tomé_, notch). A genus of Univalve shells.

PLIOCENE (Gr. _pleion_, more; _kainos_, new). The later Tertiary period.

PLIOPITHECUS (Gr. _pleion_, more; _pithekos_, ape). An extinct genus of monkeys.

PLIOSAURUS (Gr. _pleion_, more; _saura_, lizard). A genus of Plesiosaurian Reptiles.

POLYCYSTINA (Gr. _polus_, many; and _kustis_, a cyst). An order of _Protozoa_ with foraminated siliceous shells.

POLYPARY. The hard chitinous covering secreted by many of the _Hydrozoa_.

POLYPE (Gr. _polus_, many; _pous_, foot). Restricted to the single individual of a simple _Actinozoön_, such as a Sea-anemone, or to the separate zooids of a compound _Actinozoön_. Often applied indiscriminately to any of the _Coelenterata_, or even to the Polyzoa.

POLYPORA (Gr. _polus_, many; _poros_, a passage). A genus of Lace-corals (_Fenestellidoe_).

POLYTHALAMOUS (Gr. _polus_; and _thalamos_, chamber). Having many chambers; applied to the shells of _Foraminifera_ and _Cephalopoda_.

POLYZOA (Gr. _polus_; and _zoön_, animal). A division of the _Molluscoida_ comprising compound animals, such as the Sea-mat--sometimes called _Bryozoa_.

PORIFERA (Lat. _porus_, pore; and _fero_, I carry). Sometimes used to designate the _Foraminifera_, or the _Sponges_.

PRÆMOLARS (Lat. _proe_, before; _molares_, the grinders). The molar teeth of Mammals which succeed the molars of the milk-set of teeth. In man, the bicuspid teeth.

PROBOSCIDEA (Lat. _proboscis_, the snout). The order of Mammals comprising the Elephants.

PROCOELOUS (Gr. _pro_, before; _koilos_, hollow). Applied to vertebræ the bodies of which are hollow or concave in front.

PRODUCTA (Lat. _productus_, drawn out or extended). An extinct genus of Brachiopods, in which the shell is "eared," or has its lateral angles drawn out.

PROTICHNITES (Gr. _protos_, first; _ichnos_, footprint). Applied to certain impressions in the Potsdam sandstone of North America, believed to have been produced by large Crustaceans.

PROTOPHYTA (Gr. _protos_; and _phuton_, plant). The lowest division of plants.

PROTOPLASM (Gr. _protos_; and _plasso_ I mould). The elementary basis of organised tissues. Sometimes used synonymously for the "sarcode" of the _Protozoa_.

PROTOROSAURUS or PROTEROSAURUS (Gr. _protos_, first; _orao_, I see or discover; _saura_, lizard: or _proteros_, earlier; _saura_, lizard). A genus of Permian lizards.

PROTOZOA (Gr. _protos_; and _zoön_, animal). The lowest division of the animal kingdom.

PSAMMODUS (Gr. _psammos_, sand; _odous_, tooth). An extinct genus of Cestraciont Sharks.

PSEUDOPODIA (Gr. _pseudos_, falsity; and _pous_, foot). The extensions of the body-substance which are put forth by the _Rhizopoda_ at will, and which serve for locomotion and prehension.

PSILOPHYTON (Gr. _psilos_, bare; _phuton_, plant). An extinct genus of Lycopodiaceous plants.

PTERANODON (Gr. _pteron_, wing; _a_, without; _odous_, tooth). A genus of Pterosaurian Reptiles.

PTERASPIS (Gr. _pteron_, wing; _aspis_, shield). A genus of Ganoid Fishes.

PTERICHTHYS (Gr. _pteron_, wing; _ichthus_, fish). A genus of Ganoid Fishes.

PTERODACTYLUS (Gr. _pteron_, wing; _daktulos_, finger). A genus of Pterosaurian Reptiles.

PTEROPODA (Gr. _pteron_, wing; and _pous_, foot). A class of the _Mollusca_ which swim by means of fins attached near the head.

PTEROSAURIA (Gr. _pteron_, wing; _saura_, lizard). An extinct order of Reptiles.

PTILODICTYA (Gr. _ptilon_, a feather; _diktuon_, a net). An extinct genus of _Polyzoa_.

PTYCHOCERAS (Gr. _ptucé_, a fold; _keras_, a horn). A genus of _Ammonitidoe_.

PULMONATE. Possessing lungs.

PYRIFORM (Lat. _pyrus_, a pear; and _forma_, form). Pear-shaped.

QUADRUMANA (Lat. _quatuor_, four; _manus_, hand). The order of Mammals comprising the Apes, Monkeys, Baboons, Lemurs, &c.

RADIATA (Lat. _radius_, a ray). Formerly applied to a large number of animals which are now placed in separate sub-kingdoms (e.g., the _Coelenterata_, the _Echinodermata_, the _Infusoria_, &c.)

RADIOLARIA (Lat. _radius_, a ray). A division of _Protozoa_.

RAMUS (Lat. a branch). Applied to each half or branch of the lower jaw, or mandible, of Vertebrates.

RAPTORES (Lat. _rapto_, I plunder). The order of the Birds of Prey.

RASORES (Lat. _rado_, I scratch). The order of the Scratching Birds (Fowls. Pigeons, &c.)

RECEPTACULITES (Lat. _receptaculum_, a storehouse). An extinct genus of Protozoa.

REPTILIA (Lat. _repto_, I crawl). The class of the _Vertebrata_ comprising the Tortoises, Snakes, Lizards, Crocodiles, &c.

RETEPORA (Lat. _reté_, a net; _porus_, a pore). A genus of Lace-corals (_Polyzoa_).

RHAMPHORHYNCHUS (Gr. _rhamphos_, beak; _rhugchos_, nose). A genus of Pterosaurian Reptiles.

RHINOCEROS (Gr. _rhis_, the nose; _keras_, horn). A genus of Hoofed Quadrupeds.

RHIZOPODA (Gr. _rhiza_, a root; and _pous_, foot). The division of _Protozoa_ comprising all those which are capable of emitting pseudopodia.

RHYNCHOLITES (Gr. _rhugchos_, beak; and _lithos_, stone). Beak-shaped fossils consisting of the mandibles of _Cephalopoda_.

RHYNCHONELLA (Gr. _rhugchos_, nose or beak). A genus of Brachiopods.

RODENTIA (Lat. _rodo_, I gnaw). An order of the Mammals; often called _Glires_ (Lat. _glis_, a dormouse).

ROTALIA (Lat. _rota_, a wheel). A genus of _Foraminifera_.

RUGOSA (Lat. _rugosus_, wrinkled). An order of Corals.

RUMINANTIA (Lat. _ruminor_, I chew the cud). The group of Hoofed Quadrupeds (_Ungulata_) which "ruminate" or chew the cud.

SARCODE (Gr. _sarx_, flesh; _eidos_, form). The jelly-like substance of which the bodies of the _Protozoa_ are composed. It is an albuminous body containing oil-granules, and is sometimes called "animal protoplasm."

SAURIA (Gr. _saura_, a lizard). Any lizard-like Reptile is often spoken of as a "Saurian;" but the term is sometimes restricted to the Crocodiles alone, or to the Crocodiles and Lacertilians.

SAUROPTERYGIA (Gr. _sauro_; _pterux_, wing). An extinct order of Reptiles, called by Huxley _Plesiosauria_, from the typical genus _Plesiosaurus_.

SAURURÆ (Gr. _saura_; _oura_, tail). The extinct order of Birds comprising only the _Archoeopteryx_.

SCANSORES (Lat. _scando_, I climb). The order of the Climbing Birds (Parrots, Woodpeckers, &c.)

SCAPHITES (Lat. _scapha_, a boat). A genus of the _Ammonitidoe_.

SCOLITHUS (Gr. _skolex_, a worm; _lithos_, a stone). The vertical burrows of sea-worms in rocks.

SCUTA (Lat. _scutum_, a shield). Applied to any shield-like plates; especially to those which are developed in the integument of many Reptiles.

SELACHIA or SELACHII (Gr. _selachos_, a cartilaginous fish, probably a shark). The sub-order of _Elasmobranchii_ comprising the Sharks and Dog-fishes.

SEPIOSTAIRE. The internal shell of the Sepia, commonly known as the "cuttle-bone."

SEPTA. Partitions.

SERPENTIFORM. Resembling a serpent in shape.

SERTULARIDA (Lat. _sertum_, a wreath). An order of _Hydrozoa_.

SESSILE (Lat. _sedo_, I sit). Not supported upon a stalk or peduncle; attached by a base.

SETHÆ (Lat. bristles). Bristles or long stiff hairs.

SIGILLARIOIDS (Lat. _sigilla_, little images). A group of extinct plants of which _Sigillaria_ is the type, so called from the seal-like markings on the bark.

SILICEOUS (Lat. _silex_, flint). Composed of flint.

SINISTRAL (Lat. _sinistra_, the left hand). Left-handed; applied to the direction of the spiral in certain shells, which are said to be "reversed."

SIPHON (Gr. a tube). Applied to the respiratory tubes in the _Mollusca_; also to other tubes of different functions.

SIPHONIA (Gr. _siphon_, a tube). A genus of fossil Sponges.

SIPHONOSTOMATA (Gr. _siphon_; and _stoma_, mouth). The division of _Gasteropodous Molluscs_ in which the aperture of the shell is not "entire," but possesses a notch or tube for the emission of the respiratory siphon.

SIPHUNCLE (Lat. _siphunculus_, a little tube). The tube which connects together the various chambers of the shell of certain _Cephalopoda_ (_e.g._, the Pearly Nautilus).

SIRENIA (Gr. _seiren_. a mermaid). The order of _Mammalia_ comprising the Dugongs and Manatees.

SIVATHERIUM (_Siva_, a Hindoo deity; Gr. _therion_, beast). An extinct genus of Hoofed Quadrupeds.

SOLIDUNGULA (Lat. _solidus_, solid; _ungula_, a hoof). The group of Hoofed Quadrupeds comprising the Horse, Ass, and Zebra, in which each foot has only a single solid hoof. Often called _Solipedia_.

SPHENOPTERIS (Gr. _sphen_, a wedge; _pteris_, a fern). An extinct genus of ferns.

SPICULA (Lat. _spicidum_, a point). Pointed needle-shaped bodies.

SPIRIFERA (Lat. _spira_, a spire or coil; _fero_, I carry). An extinct genus of Brachiopods, with large spiral supports for the "arms."

SPIRORBIS (Lat. _spira_, a spire; _orbis_, a circle). A genus of tube-inhabiting Annelides, in which the shelly tube is coiled into a spiral disc.

SPONGIDA (Gr. _spoggos_, a sponge). The division of _Protozoa_ commonly known as sponges.

STALACTITES (Gr. _stalasso_, I drop). Icicle-like encrustations and deposits of lime, which hang from the roof of caverns in limestone.

STALAGMITE (Gr. _stalagma_, a drop). Encrustations of lime formed on the floor of caverns which are hollowed out of limestone.

STIGMARIA (Gr. _stigma_, a mark made with a pointed instrument). A genus founded on the roots of various species of _Sigillaria_.

STRATUM (Lat. _stratus_, spread out; or _stratum_, a thing spread out). A layer of rock.

STROMATOPORA (Gr. _stroma_, a thing spread out; _paras_, a passage or pore). A Palæozoic genus of _Protozoa_.

STROPHOHENA (Gr. _strophao_, I twist; _mené_, moon). An extinct genus of Brachiopods.

SUB-CALCAREOUS. Somewhat calcareous.

SUB-CENTRAL. Nearly central, but not quite.

SUTURE (Lat. _suo_, I sew). The line of junction of two parts which are immovably connected together. Applied to the line where the whorls of a univalve shell join one another; also to the lines made upon the exterior of the shell of a chambered _Cephalopod_ by the margins of the septa.

SYRINGOPORA (Gr. _surigx_, a pipe; _poros_, a pore). A genus of Tabulate Corals.

TABULÆ. (Lat. _tabula_, a tablet). Horizontal plates or floors found in some Corals, extending across the cavity of the "theca" from side to side.

TEGUMENTARY (Lat. _tegumentum_, a covering). Connected with the integument or skin.

TELEOSAURUS (Gr. _teleios_, perfect; _saura_, lizard). An extinct genus of Crocodilian Reptiles.

TELEOSTEI (Gr. _teleios_, perfect; _osteon_, bone). The order of the "Bony Fishes."

TELSON (Gr. a limit). The last joint in the abdomen of _Crustacea_; variously regarded as a segment without appendages, or as an azygous appendage.

TENTACULITES (Lat. _tentaculum_, a feeler). A genus of _Pteropoda_.

TEREBRATULA (Lat. _terebratus_, bored or pierced). A genus of _Brachiopoda_, so called in allusion to the perforated beak of the ventral valve.

TEST (Lat. _testa_, shell). The shell of _Mollusca_, which are for this reason sometimes called "_Testacea_;" also, the calcareous case of _Echinoderms_; also, the thick leathery outer tunic in the _Tunicata_.

TESTACEOUS. Provided with a shell or hard covering.

TESTUDINIDÆ (Lat. _testudo_, a tortoise). The family of the Tortoises.

TETRABRANCHIATA (Gr. _tetra_, four; _bragchia_, gill). The order of _Cephalopoda_ characterised by the possession of four gills.

TEXTULARIA. (Lat. _textilis_, woven). A genus of _Foraminifera_.

THECA (Gr. _theké_, a sheath). A genus of Pteropods.

THECODONTOSAURUS (Gr. _theké_, a sheath; _odous_, tooth; _saura_, lizard). A genus of "Thecodont" Reptiles, so named in allusion to the fact that the teeth are sunk in distinct sockets.

THERIODONT (Gr. _therion_, a beast; _odous_, tooth). A group of Reptiles so named by Owen in allusion to the Mammalian character of their teeth.

THORAX (Gr. a breastplate). The region of the chest.

THYLACOLEO (Gr. _thulakos_, a pouch; _leo_, a lion). An extinct genus of Marsupials.

TRIGONIA (Gr. _treis_, three; _gonia_, angle). A genus of Bivalve Molluscs.

TRIGONOCARPON (Gr. _treis_, three; _gonia_. angle; _karpos_, fruit). A genus founded on fossil fruits of a three-angled form.

TRILOBITA (Gr. _treis_, three; _lobos_, a lobe). An extinct order of _Crustaceans_.

TRINUCLEUS (Lat. _tris_, three; _nucleus_, a kernel). A genus of Trilobites.

TROGONTHERIUM (Gr. _trogo_, I gnaw; _therion_, beast). An extinct genus of Beavers.

TUBICOLA (Lat. _tuba_, a tube; and _colo_, I inhabit). The order of _Annelida_ which construct a tubular case in which they protect themselves.

TUBICOLOUS. Inhabiting a tube.

TUNICATA (Lat. _tunica_, a cloak). A class of _Molluscoida_ which are enveloped in a tough leathery case or "test."

TURBINATED (Lat. _turbo_, a top). Top-shaped; conical with a round base.

TURRILITES (Lat, _turris_, a tower). A genus of the _Ammonitidoe_.

UMBO (Lat. the boss of a shield). The beak of a bivalve shell.

UNGUICULATE (Lat. _unguis_, nail). Furnished with claws.

UNGULATA (Lat. _ungula_, hoof). The order of Mammals comprising the Hoofed Quadrupeds.

UNGULATE. Furnished with expanded nails constituting hoofs.

UNILOCULAR (Lat. _unus_, one; and _loculus_. a little purse). Possessing a single cavity or chamber. Applied to the shells of _Foraminifera_ and _Mollusca_.

UNIVALVE (Lat. _unus_, one; _valvoe_, folding-doors). A shell composed of a single piece or valve.

URODELA (Gr. _oura_, tail; _delos_, visible). The order of the Tailed Amphibians (Newts, &c.)

VENTRAL (Lat. _venter_, the stomach). Relating to the inferior surface of the body.

VENTRICULITES (Lat. _ventriculum_, a little stomach). A genus of siliceous Sponges.

VERMIFORM (Lat. _vermis_, worm; and _forma_, form). Worm-like.

VERTEBRA (Lat. _verto_, I turn). One of the bony segments of the vertebral column or backbone.

VERTEBRATA (Lat. _vertebra_, a bone of the back, from _vertere_, to turn). The division of the Animal Kingdom roughly characterised by the possession of a backbone.

VESICLE (Lat. _vesica_, a bladder). A little sac or cyst.

WHORL. The spiral turn of a univalve shell.

XIPHOSURA (Gr. _xiphos_, a sworn; and _oura_, tail). An order of _Crustacea_, comprising the _Limuli_ or King-Crabs, characterised by their long sword-like tails.

XYLOBIUS (Gr. _xulon_, wood; _bios_, life). An extinct genus of Myriapods, named in allusion to the fact that the animal lived on decaying wood.

ZAPHRENTIS (proper name). A genus of Rugose Corals.

ZEUGLODONTIDÆ. (Gr. _zeuglé_, a yoke; _odous_, a tooth). An extinct family of Cetaceans, in which the molar teeth are two-fanged, and look as if composed of two parts united by a neck.

ZOOPHYTE (Gr. _zoön_, animal; _phuton_, plant). Loosely applied to many plant-like animals, such as Sponges, Corals, Sea-anemones, Sea-mats, &c.

INDEX.